两次强对流背景下的对流层向平流层输送特征模拟与分析

Simulation and Analysis of Troposphere-to-Stratosphere Transport Caused by Two Severe Convection Events

为了研究强对流及其背景大尺度天气系统在对流层向平流层输送（TST）过程的作用，分别对发生在低纬度和中纬度的两次强对流天气过程进行了模拟。对于发生在广西及其附近地区的低纬度强对流天气来说，云顶温度较低，强对流所带来的直接TST输送约占总输送数的18%，强对流所在的天气尺度或大尺度的系统造成的输送约占总输送数的82%。对于发生在河北及其附近地区的中纬度强对流来说，云顶温度略高，强对流所带来的直接TST输送约占总输送数的0.17%，强对流所在的天气尺度或大尺度的系统过程造成的输送约占总输送数的99.83%。从输送到平流层以后粒子的移动方向来看，这两次过程强对流引起的直接输送都向西南方向移动，而天气尺度或大尺度系统引起的输送都向偏东方向移动。总的来说，强对流所在的背景天气尺度或大尺度的系统所引起的TST都远大于强对流的直接输送。天气尺度或大尺度的系统引起的输送一般发生在强对流发生的2天后，在强对流发生8～9天后达到最大值。

AbstractTo study the effect of the troposphere-to-stratosphere transport （TST） caused by severe convection and the associated background synoptic system, two severe convection events, one that occurred at low latitude and one at midlatitude, were simulated. In the low-latitude case, in Guangxi Province, the proportion of TST caused directly by severe convection was about 18%, while the TST caused by the synoptic background system of the severe convection was about 82%. In the midlatitude case, in Hebei Province, the proportion of TST caused directly by severe convection was about 0.17%, while the TST caused by the synoptic background system of the severe convection was about 99.83%. In terms of the motion of particles transported from the troposphere, the particles transported directly by severe convection moved towards the southwest in both events, while the particles transported by the synoptic background systems moved towards the east. In general, the amount of TST caused by the synoptic background system of the severe convection was much larger than that caused directly by the severe convection. The TST caused by the synoptic background systems occurred two days after the severe convection initiation and reached a maximum six or seven days later.